Both these books are about a journey - or rather, several journeys and one quest.

James Macdonald Lockhart sets off on 15 trips to contrasting parts of the British Isles, with a mission to find out more about 15 birds of prey. Horatio Clare travels through Europe in search of one bird that he is almost certain not to see.

The larger book, Raptor, is a hymn in praise of living, soaring, terrifying grandeur. The much shorter Orison (meaning prayer) is a sad little requiem for an exquisite creature, the slender-billed curlew, which stands on the edge of extinction. Both inspire reverence for the natural world.

The larger book, Raptor, is a hymn in praise of living, soaring, terrifying grandeur. The much shorter Orison (meaning prayer) is a sad little requiem for an exquisite creature, which stands on the edge of extinction

Lockhart sums up his ambitious project: 'To spend some time in the habitats of these birds of prey . . . beginning in the far north in Orkney and winding my way down to a river in Devon.

'A long journey south, clambering down this tall, spiny island, which is as vast and wondrous to me as any galaxy.'

The wonder is that he can write so beautifully while frozen, grubby, aching, homesick, buffeted by winds and wet - conditions that are the bird-watcher's lot.

By the end of his travels you feel these gloriously different winged creatures are more real to him than the humans he encounters along the way.

Or do I mean superior? Most raptors have eyes that are as large, if not larger, than a human's. A human eye contains around 200,000 photoreceptor cells (essential to sight) per millimetre squared, while the eye of the common buzzard 'has roughly one million of these rod-and-cone photoreceptors, enabling the buzzard to see the world in much greater detail'.

From the first page, his exquisite, poetic language is a sensuous delight without sacrificing scientific accuracy

They also see things magnified by 30 per cent; the golden eagle, for example, can pick out prey more than a kilometre away.

The Outer Hebrides is the place for these huge birds. Compared with the dashing little hobbies and merlins, he says, golden eagles do not seem to show off their speed - but can switch from a graceful soar to a deathly dive-bomb in seconds.

He notes: 'An aeroplane pilot flying down the east coast of Greece recorded being overtaken by a golden eagle while the aircraft was travelling at 70 knots.

'As the eagle passed the plane at a distance of 80 ft, the bird turned its head to glance at the aircraft before it eased past it at a speed, the pilot estimated, of 90 mph.'

Watching and waiting, he wonders why the female hen harrier rushes upwards from her nest to greet the male.

She is the larger of the pair, so what is she doing when she appears to be rising to attack him, then at the last split-second flips over on her back beneath him, so that their talons almost brush? This is the food pass.

It's tempting to think of raptors - birds of prey - as one wild mass, but Lockhart paints individualistic word-portraits of the hen harrier, merlin, golden eagle, osprey, above, and the sea eagle, goshawk and kestrel

Looking after the nest, incubating the chicks, the female depends on the male to bring food - and this is the way they do it, high in the sky so no other predator can detect the site of the nest.

This book is another reminder (and how lucky we are with the wealth of modern nature writing) that the more we observe and learn, the more likely we are to value and protect the natural world that is our heritage.

And if we don't? Horatio Clare's short book is a powerfully condensed warning.

His story of the disappearance of 'the Western world's rarest bird' would be thoroughly depressing were it not for the work of 'intensely idealistic and effective people across national boundaries' who are working to find and conserve it.

Clare's melancholy journey in search of a 'ghost' could make you weep to read (yet again) how humankind has trashed the planet and its wild things. Yet, mercifully, he offers a small counter-balance of hope.

His odyssey to places where the bird has once been glimpsed convinces him that 'passionate efforts by very small numbers of committed people can have a tremendous effect on the planet and its inhabitants, whatever their species'. Amen to that prayer.